Treatment of resins



UNITED STATES PATENT OFFICE TREATMENT OI nasnts George H. Wilder,Arlington, N. 1., animal, bymesnealaignmentatoELdnPontdeNemoursaoompany-wilmington,

Del, a corporatlonot Delaware No Drawing. Application Jane ,5, 1930,Serial No. 88,715

8Clahna. (CLzGF-Z) This invention relates to the oleflne-suiphonetroducing the treating compound into the reacresins and, moreparticularly, to a process of tion mixture in which the resin is formed,subsetreating them so as to reduce or eliminate their quent to formationof the resin, or the resin may tendency to be deteriorated anddecomposed by be separated from the reaction mixture and the heat.treating compound may be incorporated uniform- The olefine-sulphoneresins. made by the interly in it by kneading either in the presence oraction of individual oleflnes, or mixtures of oleabsence of solvent.fines, with sulfur dioxide, have certain commer- The general class ofoleiine-sulphone resins is cial advantages such as cheapness, goodappearwell known and these resi s a e O d y made ance, and readyworkability by established techy r a t with Sulfur d o de one, or amixture 10 niques. As heretofore made, however, they have f Several, 1'the fo l win leflnest been seriously handicapped because of a tendencyto decompose when heated, particularly g zg i when such heating is donein the absence of posi- V 3 2 5 tive pressure. The decomposition of theresin is P 1 l5 evidenced by a foaming and opa'cification, and en nethere is a gradual conversion of the initial therh following examples,in which all parts are mODIBStIB resin 111110 B non-thermoplasticmodigiven by weight, illustrate specific embodiments fication which isof little value because of lack of t ti of strength and because ofsusceptibility to the Example 1 1 e- 1 resin made by 20 action of Watfllkaliesand acids- This has the interaction of a mixture of butene land bubeen a ri s drawback and h Practically tene 2 and sulfur dioxideby known procedure and eluded resins of' h type from successful use incommercially available in the form of more or injection molding, forwhich these resins are less finely divided granules 1s gbjectionablyOtherwise well adapted. In inject o o din ject to decomposition by heatin the manner de- 2 the exposure of the re in to hi h mp r r is scribedabove. It is stabilized by the following ordinarily longer than in thecompression moldprocedure ing p and the te p t obtaining are To 19 partsof this resin, in a masticator mixer, likely to be higher also. is added1 part of methyl methacrylate monomer.

An object of the present invention is to pro- The mixing is continuedfor about 5 minutes 30 vide an economical and Practical Process of whichis adequate to effect a thorough incorporaing oleflne-sulnh resins so asto reduce or tionof the liquid monomer into the resin. The eliminatetheir susceptibility to decomposition temperature during mixing rangesfrom 0. 002 y heat- A further Object is to Provide Stabilized C. Theresulting homogeneous mass is then cut olcfine-su p o resins adapted tobe 111180191011 up and comminuted to give a granular molding moldedwithout d co p o Other Objects powder. This powder is not visiblydecomposed of the invention will be apparent from the deupon beinginjection molded, involving an Sc p given hereinafterposure for someminutes to temperatures of the The above objects are accomplishedaccording order of 220-250 C. 40 to the present invention by treatingoieflne-sul- Example 2.One part of methyl methacrylate 40 phone s s h ap u d av an fln monomer is added directly to 19 parts of a resin bondand select d fr m th r up nsis in of made by the interaction of amixture of butene 1 vinyl acetate. Partially polymerized Vinyl 01110-and butene 2, and sulfur dioxide, in the reaction ride, esters ofacrylic and fl y 801115, "kettle at the close of the reaction offormation courmarin, furfural, a Chloropreneof the resin. Agitation iscontinued for from 5-10 It has been discovered that the oleflne-sulphoneminutes. The relatively hot mass is then run resins are subject todecomposition by heat due out of the reaction kettle, cooled and reducedto to the presence of uncomblned residues of sulgranular iorm'. furdioxide and that these residues of sulfur di- Example 3.--Twenty partsofa butene l-sulfur oxide may readily be neutralized or eliminated,dioxide resin are treated with '1 part of mono- 50 and their harmfuleffect thus overcome, by treatmerlc glycol dimethacrylate, the two beinging the resin after completion of the reaction kneaded together in amasticator mixer until the whereby the resin is formed, with one, or amixmixture is homogeneous and plastic. This kneadture of several of thecompounds herein considing elevates the temperature somewhat but notered. This treatment may be carried out by inin excess of C. Theresulting treated resin 55 is then cut up and commlnuted to give amolding powder which is heat stable in the course of molding by theordinary technique of either compression 'or injection molding.

Example 4.-The procedure of Example 2 is carried out except thatimmediately prior to the kneading of the neutralizing agent and theresin, 5 parts of acetone are added. The temperature prevailing duringthe kneading was about 60 C.

The acetone is removed after the product has been reduced to granularform by a seasoning treatment at '70-80 C. 1

Example 5.The procedure ofExample 3 is carried out except that the resinused is one formed by the interaction of sulfur dioxide and pentene land the neutralizing agent is butyl acrylate.

Example 6.The procedure of Example 2 is carried out except that vinylacetate monomer is used in place of methyl methacrylate monomer but inthe same proportion.

Example 7.-The procedure of Example 2 is carried out with the variationthat a mixture of vinyl acetate and methyl methacrylate, in equalproportions, is substituted for the methyl methacrylate monomer.

Example 8.This is carried out as in Example 2 except that furfural isused in place of monomeric methyl methacrylate butin the sameproportions.

Example 9.-The procedure of Example 2 is carried out but employingcoumarin in place of the methyl methacrylate monomer but in the sameproportions.

The above examples are merely intended to be illustrative of the presentinvention which broadly comprises treating the olefine-sulphone resinwith one of the herein considered compounds to substantially neutralizeor remove all residues of uncombined sulfur dioxide in the resin. Theinvention is applicable to treatment of the olefine-sulphone resinsgenerally, regardless of the specific manner in which they are made,since these resins as heretofore made have been characterized by thepresence of residues of uncombined sulfur dioxide.

The compounds having an olefinic bond and suitable for neutralizing theuncombined sulfur dioxide in the olefin-sulfone resins, include vinylacetate, chloroprene, esters of acrylic acid, (e. g. methyl acrylate,butyl acrylate) esters of methacrylic acid, (e. g. methyl methacrylate,glycol methacrylate), coumarin and, in partially polymerized form, vinylchloride.

It will be understood by those skilled in the art that the proportion oftreating compound used in the treatment of specific olefine-sulphoneresins will always be relatively minor but may be varied depending uponthe amount of residues of sulfur dioxide present in the resin. Toestablish the exact amount needed for any particular resin, preliminarytests should be run. However, the treated resin is not injured even if aconsiderable excess of the treating is used. About 5%, by weight of theolefine-sulphone resin, of the treating compound can be used withoutaffecting the physical properties of the resulting product to any greatextent other than to make it stable to heat, while such proportion iseasily sufficient to neutralize the residues of uncombined sulfurdioxide in any normally made olefine-sulphone resin.

The temperature to be employed during the neutralization influences thespeed of reaction of the treating compound with the sulfur dioxideresidue, the reaction being faster at high temperatures. In general, atemperature of C. is

high enough to bring about the desired reaction at a reasonable speed inpractically every instance and much lower temperatures, 1. e., 60 C. oreven below, may be used. Temperatures above 100 C. are usually notdesirable because of the volatility of the substances involved. Thepresence of solvent permits the reaction of the treating agent with thesulfur dioxide to go forward at practically feasible rates at lowertemperatures than where the resins are treated in the absence ofsolvent.

- While the principal benefit derived from the treatment ofolefineesulphone resins according to the present invention lies in theimprovement of the resistance of the resins to heat, the removal ofresidues of uncombined sulfur dioxide also lessens the acidic characterof the resins which, when the residual sulfur dioxide is still present,have a distinctly corrosive action upon metal such as that used in moldsand also upon cellulosic fillers with which the resins may be mixed.Also, the stabilization treatment of the resins according to the presentinvention improves the resistance of the resins to water and, inparticular, decreases or eliminates the tendency of the resins to chalkas a result of contact with boiling water.

The products of the interaction of the free sulfur dioxide with thetreating agent are apparently compatible with the olefine-sulphone resinitself and not inlmlcal to the quality of the resin. The products of theinteraction are chiefly of resinous nature and either have no noticeableeffect upon the properties of the olefine-sulphone resins or exert amild and not objectionable plasticizing effect.

The present invention provides a sure and simple method of binding orneutralizing free residual sulfur dioxide in olefine-sulphone resins Iwhich has the practical beneficial effect of stabilizing the resinswhich show improved resistance to heat during molding operations andalso improved chemical inertness so that the resins no longer exert acorrosive action upon metal. There is also a distinct improvement inresistance to water and especially boiling water. While, obviously, thetreated product does contain the reaction product of the free sulfurdioxide and the treating agent used, it is essentially anolefine-sulphone resin and is characterized by its freeness fromuncombined sulfur dioxide. Other than possibly a slight plasticizingaction, the effect of the reaction product of the sulfur dioxide withthe treating agent is substantially negligible.

As many apparently widely different embodiments of this invention may bemade without departing from the spirit and scope thereof, it is to beunderstood that the invention is not limited to the specific embodimentsthereof except as defined in the appended claims.

I claim:

1. Process of treating an olefine-sulphone resin containing uncombinedresidues of sulfur dioxide which comprises intimately admixing with theresin at an elevated temperature not in excess of 100 C. methylmethacrylate in such proportion as to react with substantially all ofsaid uncombined residues of sulfur dioxide.

2. Process of treating an olefine-sulphone resin containing uncombinedresidues of sulfur dioxide which comprises intimately admixing with theresin at an elevated temperature not in excess of 100 C. coumarin insuch proportion as to react with substantially all of said uncombinedresidues of sulfur dioxide.

3. Process of treating an olefine-sulphone resin containing uncombinedresidues of sulfur dioxide which comprises intimately admixing with theresin at an elevated temperature not in excess of 100 C. vinyl acetatein such proportion as to react with substantially all of said uncombinedresidues of sulfur dioxide.

4. In the manufacture of oiefln-sulfone resins. the step comprisingtreating the resin at a temperature not in excess of 100 C. with acompound having an olefinic bond, said compound being selected from thegroup consisting of vinyl acetate, partially polymerized vinyl chloride,esters of acrylic and methacrylic acids, coumarin, furfural, andchloroprene.

5. Process of treating an oieiin-sulfone resin containing uncombinedresidues of sulfur dioxide which comprises intimately admixing with theresin at an elevated temperature not in excess of 100 C. a compoundhaving an oleflnic bond, said compound being selected from the groupconsisting of vinyl acetate, partially polymerized vinyl chloride,esters of acrylic and methacrylic acids, coumarin, furfural, andchloroprene. in such proportions as to react with substantially all ofsaid uncombined residues of sulfur dioxide.

6. Process of treating an olefin-sulfone resin containing uncombinedresidues of sulfur dioxide which comprises kneading the resin with about5% of its weight of a compound having an oleflnic bond, said compoundbeing selected from the group consisting of vinyl acetate, partiallypolymerized vinyl chloride, esters of acrylic and methacrylic acids,coumarin, Iurfural, and chloroprene, the temperature of the resin beingmaintained below 100 C. during said kneading.

7. Process of treating an oleiin-sulfone resin containing uncombinedresidues of sulfur dioxide which comprises intimately admixing with theresin in a liquid solvent medium and at an elevated temperature not inexcess of 100 C. about 5% or the weight of the resin of a compoundhaving an oletlnic bond, said compound being selected from the groupconsisting of vinyl acetate, partially polymerized vinyl chloride,esters of acrylic and methacrylic acids, coumarin, furfural, andchloroprene.

8. A plastic composition comprising an olefinsulfone resin substantiallyfree of uncombined sulfur dioxide and containing a small proportion ofthe reaction product of sulfur dioxide and a compound having an olefinicbond, said compound being selected from the group consisting of vinylacetate, partially polymerized vinyl chloride, esters of acrylic andmethacrylic acids, coumarin, furfural, and chloroprene.

GEORGE I-I. WILDER.

CERTIFICATE OF CORRECTION Patent No. 2,1li6, 276.

February 7, 1959.

GEORGE H WILDER It is hereby certified that error appears in the'printedspecification of the above numbered patent requiring correction asfollows: Page 2, first column, line 65, after the word "treating insertagent; and that the said Letters Patent should be read with thiscorrection therein that the same may conform to the record of the casein the Patent Office.

Signed and sealed this 11 th day of March, A.D. 1959.

(Seal) Henry Van Arsdale.

acting Commissioner of Patents.

